Methods and Nodes of a Wireless Network for Deciding on Switching Off of a Network Node

Abstract

The disclosure relates to a method ( 60 ) performed in a network node ( 5 a , 5 b , 8 ) of a wireless network ( 1 ) for deciding on switching off of a network node ( 5 a , 5 b ). The wireless network ( 1 ) comprises a first network node ( 5 a ) configured for wireless communication with one or more wireless devices ( 6 1 , . . . , 6 i , . . . , 6 n ) and: obtaining ( 61 ) an energy increase threshold, Thr_E i , for each wireless device ( 6 1 , . . . , 6 i , . . . , 6 n ) served by the first network node ( 5 a ); determining ( 62 ) a respective additional energy consumption E i required by each wireless device ( 6 1 , . . . , 6 i , . . . , 6 n ) served by the first network node ( 5 a ) if instead served by a neighboring network node ( 5 b , 5 c ); comparing ( 63 ), for each wireless device ( 6 1 , . . . , 6 i , . . . , 6 n ) served by the first network node ( 5 a ), the respective energy increase threshold, Thr_E i , with the respective additional energy consumption E i ; and deciding ( 64 ), based on the result of the comparing ( 63 ), whether to switch off the first network node ( 5 a ). The disclosure relates to a network node, method in wireless device, wireless device, computer programs and computer program products.

1 - 34 . (canceled) 
     
     
         35 . A method performed in a network node of a wireless network for deciding on switching off of a network node, the wireless network comprising a first network node configured for wireless communication with one or more wireless devices, the method comprising:
 obtaining an energy increase threshold, Thr_E i , for each wireless device served by the first network node;   determining a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node;   comparing, for each wireless device served by the first network node, the respective energy increase threshold, Thr_E i , with the respective additional energy consumption E i ; and   deciding, based on the result of the comparing, whether to switch off the first network node.   
     
     
         36 . The method of  claim 35 , wherein the deciding comprises deciding to switch off the first network node when the comparing reveals that each additional energy consumption E i  is smaller than or equal to each respective energy increase threshold Thr_E i . 
     
     
         37 . The method of  claim 35 , wherein the obtaining further comprises establishing for each wireless device the capability thereof to operate in a coverage enhancement mode and obtaining the capability of one or more neighboring network nodes to operate in a coverage enhancement mode. 
     
     
         38 . The method of  claim 37 , wherein the deciding further comprises deciding to switch off the first network node when the comparing reveals that each additional energy consumption E i  is smaller than or equal to each respective energy increase threshold Thr_E i  and when the establishing reveals that each wireless device has the capability to operate in a coverage enhancement mode and at least one neighboring network node has the capability to operate in the coverage enhancement mode. 
     
     
         39 . The method of  claim 35 , wherein the obtaining comprises receiving the energy increase threshold, Thr_E i , from each respective wireless device or retrieving the energy increase threshold, Thr_E i , for each wireless device from a memory or database, or determining the energy increase threshold, Thr_E i , for each wireless device based on information received from each respective wireless device, or receiving the energy increase threshold, Thr_E i , from another network node of the wireless network, or determining the energy increase threshold, Thr_E i , for each wireless device based on information received from another network node. 
     
     
         40 . The method of  claim 35 , wherein determining a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node comprises receiving from each wireless device a respective additional energy consumption E i , or calculating a respective additional energy consumption E i  required by each wireless device based on information received from each respective wireless device. 
     
     
         41 . The method of  claim 35 , wherein determining a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node comprises:
 estimating, for each wireless device, an increase of the number of repetitions, N, required for transmission and/or reception of signals to/from a neighboring network node compared to the number of repetitions required for transmission and/or reception of signals to/from the first network node, the estimating being based on signal strength between each neighboring network node and each respective wireless device, and   determining a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node based on the respective increase of number of repetitions.   
     
     
         42 . The method of  claim 41 , wherein an increase in number of repetitions is translated into additional energy consumption E i  based on time period of one signal transmission or signal reception and corresponding data rate and based on an uplink or downlink signal quality. 
     
     
         43 . The method of  claim 35 , wherein the deciding comprises deciding to switch off the first network node and the method comprises:
 for each wireless device served by the first network node, determining based on the comparing whether each wireless device is able to perform channel estimation with a reduced amount of reference signals, and   applying a reduced use of reference signals in the neighboring network node ( 5   b ,  5   c ) to be serving the wireless devices upon switching off the first network node if the determining reveals that the number of wireless devices that are able to perform channel estimation with a reduced amount of reference signals is higher than a threshold value.   
     
     
         44 . The method of  claim 35 , wherein the method is initiated upon one or more of the following triggering criteria being fulfilled: an activity level of the first network node being below an activity threshold, an energy source powering the first network node being below an energy threshold, user activity being sparsely distributed within coverage area of the first network node. 
     
     
         45 . The method of  claim 35 , comprising, when the deciding comprises deciding to switch off the first network node, informing the one or more wireless devices and any other communication devices served by the first network node about the switching off. 
     
     
         46 . The method ( 60 ) of  claim 35 , wherein the energy increase threshold, Thr_E i , comprises an additional energy consumption increase tolerable for the respective wireless device while still being operable for a set period of time. 
     
     
         47 . A network node of a wireless network configured to decide whether to switch off a network node, the wireless network comprising at least a first network node configured for wireless communication with one or more wireless devices, the network node comprising:
 a processor; and   a memory storing instructions that, when executed by the processor, causes the network node to:
 establish an energy increase threshold, Thr_E i , for each wireless device served by the first network node, 
 determine a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node, 
 compare, for each wireless device served by the first network node, the respective energy increase threshold, Thr_E i , with the respective additional energy consumption E i , and 
 decide, based on the result of the comparing, whether to switch off the first network node. 
   
     
     
         48 . The network node of  claim 47 , wherein the instructions comprise instructions to decide by deciding to switch off the first network node when the comparing reveals that each additional energy consumption E i  is smaller than or equal to each respective energy increase threshold Thr_E i . 
     
     
         49 . The network node of  claim 47 , wherein the instructions comprise instructions to obtain by further establishing for each wireless device the capability thereof to operate in a coverage enhancement mode and obtaining the capability of one or more neighboring network nodes to operate in a coverage enhancement mode. 
     
     
         50 . The network node of  claim 49 , wherein the instructions comprise instructions to decide by further deciding to switch off the first network node when the comparing reveals that each additional energy consumption E i  is smaller than or equal to each respective energy increase threshold Thr_E i  and when the establishing reveals that each wireless device has the capability to operate in a coverage enhancement mode and at least one neighboring network node has the capability to operate in the coverage enhancement mode. 
     
     
         51 . The network node of  claim 47 , wherein the instructions comprise instructions to decide by receiving the energy increase threshold, Thr_E i , from each respective wireless device or retrieving the energy increase threshold, Thr_E i , for each wireless device from a memory or database, or determining the energy increase threshold, Thr_E i , for each wireless device based on information received from each respective wireless device, or receiving the energy increase threshold, Thr_E i , from another network node of the wireless network, or determining the energy increase threshold, Thr_E i , for each wireless device based on information received from another network node. 
     
     
         52 . The network node of  claim 47 , wherein the instructions comprise instructions to determine a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node by receiving from each wireless device a respective additional energy consumption E i , or by calculating a respective additional energy consumption E i  required by each wireless device based on information received from each respective wireless device. 
     
     
         53 . The network node of  claim 47 , wherein the instructions comprise instructions to determine a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node by:
 estimating, for each wireless device, an increase of the number of repetitions, N, required for transmission and/or reception of signals to/from a neighboring network node compared to the number of repetitions required for transmission and/or reception of signals to/from the first network node, the estimating being based on signal strength between each neighboring network node and each respective wireless device, and   determining a respective additional energy consumption E i  required by each wireless device served by the first network node if instead served by a neighboring network node based on the respective increase of number of repetitions.   
     
     
         54 . The network node of  claim 53 , wherein the instructions comprise instructions to translate an increase in number of repetitions into additional energy consumption E i  based on time period of one signal transmission or signal reception and corresponding data rate and based on an uplink or downlink signal quality. 
     
     
         55 . The network node of  claim 47 , wherein the instructions comprise instructions cause the network node to, when deciding to switch off the first network node:
 for each wireless device served by the first network node, determine based on the comparing whether each wireless device is able to perform channel estimation with a reduced amount of reference signals, and   apply a reduced use of reference signals in the neighboring network node to be serving the wireless devices upon switching off the first network node if the determining reveals that the number of wireless devices that are able to perform channel estimation with a reduced amount of reference signals is higher than a threshold value.   
     
     
         56 . The network node of  claim 47 , wherein the instructions comprise instructions to initiate the decision upon one or more of the following triggering criteria being fulfilled: an activity level of the first network node being below an activity threshold, an energy source powering the first network node being below an energy threshold, user activity being sparsely distributed within coverage area of the first network node. 
     
     
         57 . The network node of  claim 47 , wherein the instructions comprise instructions to, when deciding to switch off the first network node, inform the one or more wireless devices and any other communication devices served by the first network node about the switching off. 
     
     
         58 . The network node of  claim 47 , wherein the energy increase threshold, Thr_E i , comprises an additional energy consumption increase tolerable for the respective wireless device while still being operable for a set period of time. 
     
     
         59 . A method performed in a wireless device of a wireless network for assisting a network node in deciding on switching off the network node, wherein the wireless network comprises a first network node configured for wireless communication with the wireless device, the method comprising:
 obtaining an energy increase threshold, Thr_E i , for the wireless device served by the first network node,   estimating an additional energy consumption E i  required by the wireless device served by the first network node if instead served by a neighboring network node, and   transmitting to the first network node a message indicating the additional energy consumption E i  and/or a comparison between the energy increase threshold, Thr_E i , and the additional energy consumption E i .   
     
     
         60 . The method of  claim 59 , further comprising estimating an additional energy consumption Ei required by the wireless device if the wireless device is to operate in a coverage enhancement mode with one or more neighboring network nodes. 
     
     
         61 . The method of  claim 59 , comprising transmitting to the first network node one or more of: a value representing number of repetitions of a signal needed for a transmission of a given message size on the basis of a received signal strength, a difference of number of repetitions of a signal needed if switching from the first network node to a neighboring network node on the basis of a received signal strength to the respective neighboring network node, estimated difference of repetitions of a signal needed for correct transmission and reception of a given message size if switching to a neighboring network node. 
     
     
         62 . A wireless device of a wireless network for assisting a network node in deciding on switching off of a network node, wherein the wireless network comprises a first network node configured for wireless communication with the wireless device, the wireless device comprising:
 a processor; and   a memory storing instructions that, when executed by the processor, causes the wireless device to:
 establish an energy increase threshold, Thr_E i , for the wireless device served by the first network node, 
 estimate an additional energy consumption E i  required by the wireless device served by the first network node if instead served by a neighboring network node, and 
 transmit to the first network node a message indicating the additional energy consumption E i  and/or a comparison between the energy increase threshold, Thr_E i , and the additional energy consumption E i . 
   
     
     
         63 . The wireless device of  claim 62 , wherein the instructions comprise instructions to estimate an additional energy consumption Ei required by the wireless device if the wireless device is to operate in a coverage enhancement mode with one or more neighboring network nodes. 
     
     
         64 . The wireless device of  claim 64 , wherein the instructions comprise instructions to transmit to the first network node one or more of: a value representing number of repetitions of a signal needed for a transmission of a given message size on the basis of a received signal strength, a difference of number of repetitions of a signal needed if switching from the first network node to a neighboring network node on the basis of a received signal strength to the respective neighboring network node, estimated difference of repetitions of a signal needed for correct transmission and reception of a given message size if switching to a neighboring network node.